We'd like to install a timer with freeze protection and have a recommendation for the Intermatic INT PF1103T. Our 7.5 hp pump currently is operated by a Stingl switch. Two concerns. The brochure has the INT PF1103T rated for single phase and 3 hp. Can I use this timer with my pump using one of the 3 phases? (I'm pretty sure that's how the Stingl switch was installed). Can I install it side by side with the Stingl and switch back and forth? We actually don't need the Stingl anymore since we have our full VGB certification. Thanks.
Timer with freeze protection
- Thread starter FredW
- Start date
No you can't switch just one leg of a three phase motor circuit. You have to switch at least two legs and I highly recommend switching all three.
Do you have a motor starter in the MCC or an external enclosure? If so you can switch the control circuit through the timer and be fine that way.
Do you have a motor starter in the MCC or an external enclosure? If so you can switch the control circuit through the timer and be fine that way.
So here's where I confess my lack of electrical knowledge. I'll describe the set up and maybe that will clarify the situation.
The Stingl switch box has written in it "120V connections to coil". There are 2 separate conduit lines, one each running from the pump motor and the Stingl switch into a first box labeled "Contactor Pump, 208V 3ph, coil 120V". Out of this box runs a single line into the main disconnect (on/off handle on the side) that is labeled "Switch Disconnect Pump, 3 ph 208 V".
BTW, I won't be attempting this install myself. Just trying to make sure I get the right product before I call in my electrical guy.
Thanks.
The Stingl switch box has written in it "120V connections to coil". There are 2 separate conduit lines, one each running from the pump motor and the Stingl switch into a first box labeled "Contactor Pump, 208V 3ph, coil 120V". Out of this box runs a single line into the main disconnect (on/off handle on the side) that is labeled "Switch Disconnect Pump, 3 ph 208 V".
BTW, I won't be attempting this install myself. Just trying to make sure I get the right product before I call in my electrical guy.
Thanks.
What you have is a 3 phase motor starter energized by a 120volt coil. Switching the coil circuit with a 120 volt timer is fine. Actually, it's preferred! You'll be fine using the Intermatic timer.